Pressure sensitive labels applied are applied to packages to build brand awareness, show the contents of the package, convey a quality message regarding the contents of a package and supply consumer information such as directions on product use, or an ingredient listing of the contents. Printing on the pressure sensitive label is typically applied directly to the package or a printed media, typically printed using gravure printing or flexography is applied to the package. The three types of information are typically applied to a pressure sensitive label are text, graphic and images. Prior art printed labels are typically die cut to remove pragmatic sheet and pressure sensitive adhesive in the areas that are not imaged. Rolls of imaged, die cut labels, which are free from adhesive at the edges, are provided to packing labeling operations. While the die cut imaged prior art labels are free from adhesive at the edges, the labels are also cut in the cross direction yielding a roll of discrete imaged labels.
Photographic materials have been known for use as prints for preserving memories for special events such as birthdays and vacations. They also have been utilized for large display materials utilized in advertising. These materials have been known as high quality products that are costly and somewhat delicate as they would be easily defaced by abrasion, water, or bending. Photographs are traditionally placed in frames, photo albums, and behind protective materials in view of their fragile and delicate nature, as well as their value. They are considered luxury items for the consumers to preserve a record of important events in their lives. They also have been considered as expensive display materials for advertising. In view of their status as luxury items, they have not been utilized in other areas of commerce.
Typically pressure sensitive labels are supplied with a carrier web material that allows the pressure sensitive label to be transported though the printing process and converting process while protecting the adhesive. Prior art carrier materials typically comprise a coated paper or a thin polymer carrier on to which a release coating is subsequently provided. Carrier materials typically utilized in the pressure sensitive label are not suitable for a photographic label. Problems such as photographic reactivity with the light sensitive layers, lack of stiffness of the carrier and edge penetration of processing chemistry into the paper used as a carrier prevent typical polymer and paper carriers from being utilized for photographic pressure sensitive labels.
Prior art ink printed labels that are applied to packages consist of a pragmatic sheet material, a pressure sensitive adhesive and a carrier. The label substrate consisting of the pragmatic sheet, pressure sensitive adhesive and carrier are typically laminated and then printed utilizing a variety of non photographic printing methods. After printing, the labels are generally protected by an over laminate material or a protective coating. The completed label consisting of a protection layer, printed information, pragmatic sheet, pressure sensitive adhesive and carrier material is applied to packages utilizing high speed labeling equipment. During the conversion of pressure sensitive web materials into labels, the pressure sensitive web materials consisting of a pragmatic sheet, carrier, pressure sensitive and release coating are printed in equipment that is center guided, that is the label web materials do not contact machine frames, guides or spacers. Repeated edge contact of pressure sensitive web materials against machine guides, for example, would likely result in adhesive transfer from the pressure sensitive web to the machine guide resulting in unwanted adhesive build up on the edge guide.
In order for light sensitive silver halide imaging layers to be utilized for pressure sensitive labels, the exposed pressure sensitive adhesive at the edges of light sensitive silver halide web materials must be significantly reduced so that the transfer of pressure sensitive adhesive to edge guide equipment typically found in photographic printers is eliminated. The transfer of pressure sensitive adhesive to edge guided photographic printers results in loss of printing efficiency, printing defects and web fracture.
During the manufacturing of color paper it is necessary to cut the material lengthwise prior to its exposure, to reach suitable size for customer use. The photographic paper is formed in long, wide sheets, then spooled into large rolls. These rolls must be slit to suitable widths in a very accurate manner. It is important that the slitting be performed without damage to the sensitive photographic materials that are on the paper substrate. Further, it is important that slitting be performed without creation of substantial dust which might lead to undesirable contamination of picture surfaces after development.
Generally the knives utilized for cutting photographic papers have been arrangements of circular knives on shafts, with the paper being fed between the shafts with knives. The circular knives are brought together such that they touch and overlap slightly at the edge. It is common for one knife to have a square edge called the female knife, and the other knife to be ground at some angle, this knife called a male knife. In this way, many strips can be simultaneously slit from a wide sheet. U.S. Pat. No. 5,365,821—Munier et al discloses such a cutting device. EP 0 737 552—Blandin also discloses a knife and anvil cutting device. U.S. Pat. No. 5,974,922 Camp et al discloses knife geometry to provide acceptable slit edge for photographic color paper. It has been found that shear slitting of a web material containing a pressure sensitive adhesive produces a slit roll that is tacky and prone to adhesive transfer during edge guiding.
There are also known in the art methods for slitting and sealing two or more materials using light beams from a laser instead of heated knives. Because light beams generated by lasers are more precise energy transfer devices than heated knives, laser-based methods typically result in cleaner seals where fusing is involved. One example of a laser slitting and sealing method is found in U.S. Pat. Nos. 4,414,051 and 4,490,203 (Bose et al), disclosing a method whereby a laser beam slits and seals an extrusion blown tube into two or more tubes. The Bose patents focus on reduced bead formation at slit/seal points and improved seal strength. Other laser slitting and sealing methods include: U.S. Pat. No. 5,630,308 (Guckenberger et al), disclosing a method of laser scoring packaging substrates to form an easy opening tear control package such as a pouch; U.S. Pat. Nos. 5,502,292 and 5,500,503 (Pernicka et al.), disclosing a method of simultaneously cutting and welding ultra thin metallic foil materials using a pulsed laser; and U.S. Pat. Nos. 5,314,767 and 5,455,129 to Bussard, disclosing a holographic product having sealed edges. In Bussard, a plastic top layer of the holographic product can be simultaneously cut and sealed with a variety of cutting tools including a laser. In U.S. Pat. No. 6,103,050 (Krueger) a method of laser slitting and sealing two polymeric sheets is proposed. In U.S. Pat. No. 6,103,050 the sealing of the two sheets would counter productive to providing a pragmatic sheet that can be removed from a carrier sheet.